Which of the following is an example of a freemium pricing strategy?

A$.$ Customers can listen to some songs on Spotify for free but if they pay a monthly fee they can listen ad$-$free to any song they want.

B$.$The grocery store advertises low prices on eggs and milk to get customers into the store to buy other products.

C$.$The maker of robots figures out how much a company will save using its product to help guide its pricing strategy.

D$.$The book store gives out books to children for free to promote literacy in its community.

E$.$Everything in the tourist shop is less than $$50$ and ends in the number $5$ or the number $9.$